But on Oct. 3 — 45 miles from where student Paul DeWolf was killed in his Ann Arbor fraternity — a man in Detroit attempted to log onto a computer he’d just purchased through Craigslist. The man didn’t know it, but the Mac laptop had been stolen from DeWolf’s next-door neighbor around the time he was killed.

That computer had an app that would lead police directly to it, and to the two suspects now charged in DeWolf’s killing. . . .

On Oct. 3, Apple was alerted that the stolen Apple Air computer was turned on, and its contents were erased. Police traced the computer to a home on Glynn Court in Detroit, and a man there said he got the computer from an Ypsilanti man through Craigslist.

The new owner, a 30-year-old man who asked not to be identified, told the Free Press he’d suspected the laptop was stolen because when he connected to the Internet, the screen locked. But the man who sold him the computer tried to help him with the password, so, he said, he thought perhaps it was locked by an ex-girlfriend.

Then the police showed up.

“I knew it was something more than a stolen laptop since Ann Arbor police came all the way here,” he said. . . .

Authorities took the computer and his cell phone, which he said he offered to help with the investigation.

Police used it to identify the Ypsilanti man who sold the computer and learned that on July 25 — a day after DeWolf, 25, was discovered dead in his basement apartment — the Ypsilanti man bought the stolen computer from Jordan for $200. . . .